特性

全部特性:

• 通过统一的API访问Cache系统
• 通过注解实现声明式的方法缓存，支持TTL和两级缓存
• 通过注解创建并配置Cache实例
• 针对所有Cache实例和方法缓存的自动统计
• Key的生成策略和Value的序列化策略是可以配置的
• 分布式缓存自动刷新，分布式锁 (2.2+)
• 异步Cache API (2.2+，使用Redis的lettuce客户端时)
• Spring Boot支持

JetCache整合srpingboot配置

maven配置

   <!--注意版本要对应，不然会报错--><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.2.5.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><dependency><groupId>com.alicp.jetcache</groupId><artifactId>jetcache-starter-redis</artifactId><version>2.6.0</version></dependency><!--可能要加--><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><version>3.8.0</version><configuration><source>1.8</source><target>1.8</target><compilerArgument>-parameters</compilerArgument></configuration></plugin>

application.yml配置

jetcache:statIntervalMinutes: 1areaInCacheName: falselocal:default:type: caffeinelimit: 100keyConvertor: fastjsonremote:default:type: rediskeyConvertor: fastjsonvalueEncoder: javavalueDecoder: javapoolConfig:minIdle: 5maxIdle: 20maxTotal: 50host: 47.98.129.125port: 6379#password:***#sentinels: 127.0.0.1:26379 , 127.0.0.1:26380, 127.0.0.1:26381#masterName: mymaster

使用JavaConfig配置（与application.yml配置二选一）

@Configuration
@EnableMethodCache(basePackages = "com.example.demo.cache")
@EnableCreateCacheAnnotation
public class JetCacheConfig {@Beanpublic Pool<Jedis> pool() {GenericObjectPoolConfig pc = new GenericObjectPoolConfig();pc.setMinIdle(2);pc.setMaxIdle(10);pc.setMaxTotal(10);return new JedisPool(pc, "47.98.129.125", 6379);}@Beanpublic ConfigProvider configProvider() {return new ConfigProvider();}@Beanpublic GlobalCacheConfig config( Pool<Jedis> pool) {Map localBuilders = new HashMap();EmbeddedCacheBuilder localBuilder = CaffeineCacheBuilder.createCaffeineCacheBuilder().limit(100).keyConvertor(FastjsonKeyConvertor.INSTANCE);localBuilders.put(CacheConsts.DEFAULT_AREA, localBuilder);Map remoteBuilders = new HashMap();RedisCacheBuilder remoteCacheBuilder = RedisCacheBuilder.createRedisCacheBuilder().keyConvertor(FastjsonKeyConvertor.INSTANCE).valueEncoder(JavaValueEncoder.INSTANCE).valueDecoder(JavaValueDecoder.INSTANCE).jedisPool(pool);remoteBuilders.put(CacheConsts.DEFAULT_AREA, remoteCacheBuilder);GlobalCacheConfig globalCacheConfig = new GlobalCacheConfig();globalCacheConfig.setLocalCacheBuilders(localBuilders);globalCacheConfig.setRemoteCacheBuilders(remoteBuilders);globalCacheConfig.setStatIntervalMinutes(15);globalCacheConfig.setAreaInCacheName(false);return globalCacheConfig;}
}

常用注解

启动类上加注解，开启缓存：

@EnableMethodCache(proxyTargetClass = true,basePackages = "com.shinemo.migu.activity.thirdapi.core")
@EnableCreateCacheAnnotation

方法上的注解

获取时：

@Cached(name = "award.getById", key = "#id", cacheType = CacheType.LOCAL, expire = 300)

修改时:

 @CacheUpdate(name="userCache-", key="#user.userId", value="#user")void updateUser(UserDO user);

删除时：

@CacheInvalidate(name = "userService2.getUserById", key = "#id")

代码示例：

@Service
public class UserService2 {@Autowiredprivate UserDao userDao;@Cached(name = "userService2.getUserById", key = "#id", cacheType = CacheType.BOTH, expire = 60*5)@CacheRefresh(refresh = 10, stopRefreshAfterLastAccess = 60)public UserDO getUserById(Integer id) {UserDO userDO = userDao.selectById(id);return userDO;}public void addUser(UserDO user) {userDao.insert(user);}@CacheUpdate(name = "userService2.getUserById", key = "#user.id",value = "#user" )public void updateUser(UserDO user) {userDao.updateById(user);}@CacheInvalidate(name = "userService2.getUserById", key = "#id")public void deleteUser(Integer id) {//userDao.deleteById(id);}
}

实例变量上的注解

创建缓存实例：

@CreateCache(cacheType = CacheType.LOCAL, name = "jobActivityCache", timeUnit = TimeUnit.MINUTES, expire = 5)
private Cache<Integer,UserDO> userCache;@CreateCache(name = "UserService.userCache", expire = 100, cacheType = CacheType.BOTH, localLimit = 50)
private Cache<Long, UserDO> userCache;

代码示例：

@Service
public class UserService {@CreateCache(name = "UserService.userCache", cacheType = CacheType.REMOTE, localLimit = 50,expire = 60*5)private Cache<Integer, UserDO> userCache;@Autowiredprivate UserDao userDao;public UserDO getUserById(Integer id) {UserDO userDO = userCache.get(id);if (userDO == null) {UserDO userDB = userDao.selectById(id);if (userDB == null) {throw new RuntimeException("数据不存在");}userCache.put(id, userDB);return userDB;}return userDO;}public void addUser(UserDO user) {userDao.insert(user);}public void updateUser(UserDO user) {userDao.updateById(user);userCache.put(user.getId(), user);}public void deleteUser(Integer id) {//userDao.deleteById(id);userCache.remove(id);}
}

刷新缓存

@CacheRefresh

刷新缓存,可以加在方法上，也可以加在实例上：

@CacheRefresh(refresh = 60, stopRefreshAfterLastAccess = 300) //60秒刷新一次，如果300秒内没有访问，则停止刷新

cacheType为REMOTE或者BOTH的时候，刷新行为是全局唯一的，也就是说，即使应用服务器是一个集群，也不会出现多个服务器同时去刷新一个key的情况。
一个key的刷新任务，自该key首次被访问后初始化，如果该key长时间不被访问，在stopRefreshAfterLastAccess指定的时间后，相关的刷新任务就会被自动移除，这样就避免了浪费资源去进行没有意义的刷新。

@CachePenetrationProtect

@CachePenetrationProtect表示在多线程环境中同步加载数据。

高级API

异步API

CacheGetResult r = cache.GET(userId);
CompletionStage<ResultData> future = r.future();
future.thenRun(() -> {if(r.isSuccess()){System.out.println(r.getValue());}
});

分布式锁

cache.tryLockAndRun("key", 60, TimeUnit.SECONDS, () -> heavyDatabaseOperation());

设置读取器并自动刷新

    @CreateCache(name = "UserService3.userCache",timeUnit = TimeUnit.SECONDS,expire = 1000,cacheType = CacheType.BOTH)@CacheRefresh(timeUnit = TimeUnit.SECONDS, refresh = 30, stopRefreshAfterLastAccess = 600)@CachePenetrationProtectprivate Cache<String, List<UserDO>> userCache;@PostConstructpublic void init(){userCache.config().setLoader(this::loadUser);}public List<UserDO> loadUser(String key) {List<UserDO> userDOS = userDao.selectList(null);return userDOS;}